Department of Epidemiology, University of Florida, College of Public Health and Health Professions, College of Medicine, 2004 Mowry Road, PO Box 100231, Gainesville, FL 32610, United States; Emerging Pathogens Institute, University of Florida, 2055 Mowry Road, PO Box 100009, Gainesville, FL 32610, United States.
Emerging Pathogens Institute, University of Florida, 2055 Mowry Road, PO Box 100009, Gainesville, FL 32610, United States; Division of Infectious Diseases and Global Medicine, University of Florida, College of Medicine, 2055 Mowry Road, PO Box 103600, Gainesville, FL 32610, United States.
Infect Genet Evol. 2024 Sep;123:105648. doi: 10.1016/j.meegid.2024.105648. Epub 2024 Jul 25.
The Beijing genotype of Mycobacterium tuberculosis (Mtb) has sparked debate regarding its virulence and transmissibility. This study contributes to this discussion by assessing its effect on the risk of latent tuberculosis infection (LTBI), active tuberculosis (TB) disease among contacts, and clustering of known TB cases.
We conducted a retrospective cohort study using the records of 4457 culture-confirmed TB patients and their contacts (20,448) reported to the Florida Department of Health between 2009 and 2023. Univariate and multivariate analyses were used to evaluate the effect of the Beijing strain on LTBI, active TB risk among contacts, and case clustering.
Our study revealed no significant difference in transmissibility between the Beijing and non-Beijing genotypes among contacts. LTBI prevalence was 19.9%, slightly higher in non-Beijing than Beijing genotypes (20.2% vs. 15.5%, p < 0.001). The prevalence of active TB was 1.8%, with no significant difference between the Beijing and non-Beijing genotypes (1.4% vs. 1.8%, p = 0.296). Increased LTBI risk was associated with older age, male sex, Hispanic ethnicity, multidrug-resistant TB exposure, household exposure, and a longer exposure duration. Active TB risk was higher for males, HIV-positive individuals, and contacts with more prolonged exposure to index cases. The Beijing genotype was associated with increased TB case clustering (aOR = 1.98, 95%CI: 1.53, 2.55, p < 0.001) as compared to the non-Beijing genotypes. US birthplace (aOR = 2.75, 95%CI: 2.37, 3.19, p < 0.001), pulmonary disease (aOR = 1.27, 95%CI: 1.04, 1.56, p < 0.020), cavitary TB (aOR = 1.25, 95% CI: 1.08, 1.44, p < 0.003), previous year alcohol use (aOR = 1.68, 95%CI: 1.38, 2.04, p < 0.001), and recreational drug use (aOR = 1.32, 95%CI: 1.04, 1.67, p < 0.024) were also associated with an increased risk of TB case clustering.
While the Beijing genotype did not increase the risk of LTBI or active TB among contacts, it showed a higher tendency for case clustering. Hence, interventions should prioritize populations where this genotype is prevalent.
结核分枝杆菌（Mtb）的北京基因型引发了关于其毒力和传染性的争论。本研究通过评估其对潜伏性结核感染（LTBI）风险、接触者中活动性结核病（TB）发病风险以及已知 TB 病例的聚集性的影响，为这一讨论做出了贡献。
我们使用 2009 年至 2023 年期间向佛罗里达州卫生部报告的 4457 例培养确诊的 TB 患者及其接触者（20448 人）的记录进行了回顾性队列研究。使用单变量和多变量分析评估了北京株对 LTBI、接触者中活动性 TB 风险以及病例聚集性的影响。
我们的研究并未发现北京和非北京基因型之间在接触者中的传染性有显著差异。LTBI 患病率为 19.9%，非北京基因型略高于北京基因型（20.2% vs. 15.5%，p<0.001）。活动性 TB 的患病率为 1.8%，北京和非北京基因型之间无显著差异（1.4% vs. 1.8%，p=0.296）。年龄较大、男性、西班牙裔、耐多药结核接触史、家庭接触和接触时间较长与 LTBI 风险增加相关。男性、HIV 阳性个体和接触者与索引病例的接触时间较长，其活动性 TB 发病风险更高。与非北京基因型相比，北京基因型与 TB 病例聚集性增加相关（优势比[OR]：1.98，95%置信区间[CI]：1.53，2.55，p<0.001）。与非北京基因型相比，美国出生（OR：2.75，95%CI：2.37，3.19，p<0.001）、肺部疾病（OR：1.27，95%CI：1.04，1.56，p<0.020）、空洞性结核病（OR：1.25，95%CI：1.08，1.44，p<0.003）、前一年饮酒（OR：1.68，95%CI：1.38，2.04，p<0.001）和娱乐性药物使用（OR：1.32，95%CI：1.04，1.67，p<0.024）也与 TB 病例聚集性增加相关。
尽管北京基因型并未增加接触者中 LTBI 或活动性 TB 的风险，但它显示出更高的病例聚集倾向。因此，干预措施应优先针对该基因型流行的人群。
